Physiological reactivity to infant crying: a behavioral genetic study.

In this study, we examined adults' cardiac reactivity to repeated infant cry sounds in a genetically informative design. Three episodes of cry stimuli were presented to a sample of 184 adult twin pairs. Cardiac reactivity increased with each cry episode, indicating that subjects were increasingly sensitized to repeated infant distress signals. Non-parents showed more cardiac reactivity than parents, and males displayed a larger increase in heart rate (HR) in response to repeated cry sounds than females. Multivariate genetic modeling showed that the genetic component of adults' HR while listening to infant crying was substantial. Genetic factors explained 37-51% of the variance in HR and similar genes influenced HR at baseline and HR reactivity to infant crying. The remaining variance in HR across the cry paradigm was accounted for by unique environmental influences (including measurement error). These results point to genetic and experiential effects on HR reactivity to infant crying that may contribute to the explanation of variance in sensitive and harsh parenting.

A national human neuroimaging collaboratory enabled by the Biomedical Informatics Research Network (BIRN).

The aggregation of imaging, clinical, and behavioral data from multiple independent institutions and researchers presents both a great opportunity for biomedical research as well as a formidable challenge. Many research groups have well-established data collection and analysis procedures, as well as data and metadata format requirements that are particular to that group. Moreover, the types of data and metadata collected are quite diverse, including image, physiological, and behavioral data, as well as descriptions of experimental design, and preprocessing and analysis methods. Each of these types of data utilizes a variety of software tools for collection, storage, and processing. Furthermore sites are reluctant to release control over the distribution and access to the data and the tools. To address these needs, the Biomedical Informatics Research Network (BIRN) has developed a federated and distributed infrastructure for the storage, retrieval, analysis, and documentation of biomedical imaging data. The infrastructure consists of distributed data collections hosted on dedicated storage and computational resources located at each participating site, a federated data management system and data integration environment, an Extensible Markup Language (XML) schema for data exchange, and analysis pipelines, designed to leverage both the distributed data management environment and the available grid computing resources.

Robot-assisted needle placement in open MRI: system architecture, integration and validation.

In prostate cancer treatment, there is a move toward targeted interventions for biopsy and therapy, which has precipitated the need for precise image-guided methods for needle placement. This paper describes an integrated system for planning and performing percutaneous procedures with robotic assistance under MRI guidance. A graphical planning interface allows the physician to specify the set of desired needle trajectories, based on anatomical structures and lesions observed in the patient's registered pre-operative and pre-procedural MR images, immediately prior to the intervention in an open-bore MRI scanner. All image-space coordinates are automatically computed, and are used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template. Automatic alignment of real-time intra-operative images aids visualization of the needle as it is manually inserted through the guide. Results from in-scanner phantom experiments are provided.

Robot-assisted needle placement in open-MRI: system architecture, integration and validation.

This work describes an integrated system for planning and performing percutaneous procedures-such as prostate biopsy-with robotic assistance under MRI-guidance. The physician interacts with a planning interface in order to specify the set of desired needle trajectories, based on anatomical structures and lesions observed in the patient's MR images. All image-space coordinates are automatically computed, and used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template. Direct control of real-time imaging aids visualization of the needle as it is manually inserted through the guide. Results from in-scanner phantom experiments are provided.

An enabling system for echocardiography providing adaptive support through behavioral analysis.

Echocardiography requires the integrated application of a broad spectrum of cognitive and practical skills, e.g. diagnostic knowledge (symbolic), image interpretation (visual perception) and handling of the ultrasound probe (sensorimotor). This complex expertise is acquired through extensive practical training guided by a skilled cardiologist that is often incompatible with clinical reality. Especially for beginners, the most critical point during an echocardiographic examination is the steering of the ultrasound probe to navigate between different cardiological standard planes (sensorimotor skill) without loosing orientation. These transitions or "standard trajectories" can roughly be described by specific movement patterns. We propose an enabling system based on an Augmented Reality simulator for two-dimensional echocardiography imitating this apprenticeship [1]-[3]. During a simulated ultrasound examination the system monitors the activities of the trainee and analyzes the motion pattern of the ultrasound probe. The simulator reacts by mapping the motion patterns onto cognitive orientation demands and providing adaptive feedback in the form of context sensitive help (animations). It partly takes the role of the critical teacher.

[Augmented reality in echocardiography. A new method of computer-assisted training and image processing using virtual and real three-dimensional data sets]. / Augmented Reality in der Echokardiographie--Eine neue Methode der computergestützten Ausbildung und Bildbearbeitung durch virtuelle und reale dreidimensionale Datensätze.

Augmented reality (AR) applications link real with virtual image data, in order to increase their information content. In medicine they are especially useful for education and for supporting the interpretation of three-dimensional (3D) image data. Simulators are used to train risky or expensive procedures. In the AR application EchoCom2 a 3D surface model of the human heart is linked with echocardiographic volume data sets. The 3D echocardiographic data sets are registered with the heart model to synchronize it's temporal and spatial orientation. The heart model together with an animated ultrasound sector represents a reference scenario, which displays the currently selected cutting plane within the echocardiographic volume data set. Modifications of the cutting plane within the echocardiographic data are transferred simultaneously and in real time to the reference scenario. The AR application is used as a simulator to train two-dimensional echocardiographic examinations and as an orientation and navigation aid for the exploration of 3D echocardiographic data sets. Beginners in echocardiography have only a rudimentary conception of the spatial relationship between the actual ultrasound image and the 3D anatomy of the heart. They are unable to translate multiple two-dimensional slices into a coherent 3D mental image of the heart. In EchoCom2 the trainee can interactively explore the 3D heart model and the registered 3D echocardiographic data sets by the animated ultrasound sector, whose position is controlled by an electromagnetic orientation and position system (EPOS). The data from the EPOS are used to calculate the echocardiographic images that are analogue to the position of the animated ultrasound sector. EchoCom2 is also used to support the interpretation of 3D echocardiographic data sets. The analysis of 3D echocardiographic data has to be done during a post processing. Defining the exact position of a cutting plane within the volume is difficult due to the lack of a standardized representation, the independence of the cutting plane of any transducer position and the possibility to calculate an indefinite number of views. The simultaneous representation of the current cutting plane both in the volume data, and in the heart model enables the examiner ad hoc to recognize it's position and the visualized structures.

Augmented reality simulator for training in two-dimensional echocardiography.

In two-dimensional echocardiography the sonographer must synthesize multiple tomographic slices into a mental three-dimensional (3D) model of the heart. Computer graphics and virtual reality environments are ideal to visualize complex 3D spatial relationships. In augmented reality (AR) applications, real and virtual image data are linked, to increase the information content. In the presented AR simulator a 3D surface model of the human heart is linked with echocardiographic volume data sets. The 3D echocardiographic data sets are registered with the heart model to establish spatial and temporal congruence. The heart model, together with an animated ultrasound sector represents a reference scenario, which displays the currently selected two-dimensional echocardiographic cutting plane calculated from the volume data set. Modifications of the cutting plane within the echocardiographic data are transferred and visualized simultaneously and in real time within the reference scenario. The trainee can interactively explore the 3D heart model and the registered 3D echocardiographic data sets by an animated ultrasound probe, whose position is controlled by an electromagnetic tracking system. The tracking system is attached to a dummy transducer and placed on a plastic puppet to give a realistic impression of a two-dimensional echocardiographic examination.

Thoracoscopically assisted ligamentous release of the thoracic spine: a cadaver study.

The surgical treatment of thoracic kyphosis frequently requires an anterior release, which can be carried out by an open or endoscopic technique. This study concerns the reference points which are essential from the anatomic view for minimizing the operative risks. Furthermore we wanted to find the most convenient video-assisted thoracoscopic surgery (VATS) technique for transection of the anterior longitudinal ligament (ALL). Transection of the ALL, as well as discectomy, was performed using this technique. The extensive anatomic dissection of 12 fresh cadavers was performed to define possible technical errors and surgical complications. The development of new instruments has made the VATS approach to the ALL a viable alternative to open procedures. With the help of a standardized technique, the isolated thoracoscopic ligamentous transection required less time than the comparable open procedure. The anatomic study showed, that in no case was a ligation of the intercostal or segmental vessels necessary as part of the approach to the spine, once an adequate mobilization of the esophagus and azygos vein had been carried out. The risk of an ischemic lesion of the spinal cord was thereby reduced. The thoracoscopic, limited anterior release consisting of a multilevel transection of the ALL proved to be a rapid and reliable procedure. Our anatomic studies provides suitable the reference points.

Bradykinin modulates arginine vasopressin-induced calcium influx in vascular myocytes.

UNLABELLED: We investigated direct, endothelium-independent effects of bradykinin on arginine vasopressin-induced calcium influx in vascular smooth muscle cells. We studied cultured rat vascular smooth muscle cells by using the whole-cell voltage-clamp and calcium fluorescence imaging methods. Exposing cultured vascular smooth muscle cells (A7r5 cell line) to arginine vasopressin (100 nM) produced a transient increase in [Ca2+]i, followed by a sustained increase in [Ca2+]i. This was readily reversible (n=28). At a holding potential of -40 to -60 mV, arginine vasopressin induced a sustained inward current correlated with a sustained increase in [Ca2+]i. Bradykinin (30 nM to 30 microM) had no effect on arginine vasopressin-induced [Ca2+]i transients. However, during the sustained phase of increased [Ca2+]i, bradykinin reversibly attenuated relative fluorescence and inward current in the presence of arginine vasopressin (n=14). This was concentration dependent and inhibited by [D-Phe7]-bradykinin (30 microM), a kinin receptor antagonist. Also, sustained arginine vasopressin-mediated increases in [Ca2+]i and inward current were attenuated by Ca2+-free or La3+-supplemented perfusate but not by nifedipine (n=5). CONCLUSIONS: (1) Bradykinin can attenuate arginine vasopressin-induced and sustained Ca2+ influx and sustained inward current through a novel endothelium-independent process. (2) The direct effect of bradykinin on arginine vasopressin-induced increases in [Ca2+]i sustained Ca2+ influx in vascular smooth muscle cells is concentration dependent and kinin-receptor mediated. (3) Arginine vasopressin-induced sustained [Ca2+]i elevation correlates with the activation of a dihydropyridine-insensitive, Ca2+-conducting inward current.

Screening of selected basidiomycetes for inhibitory activity on neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE).

Aqueous extracts of 27 basidiomycetes were investigated for their ability to inhibit the activity of angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP). The extracts of 5 fungi inhibited both, ACE and NEP activity, another 18 extracts showed inhibition of the NEP activity whereas only 1 basidiomycete inhibited the ACE activity exclusively. The IC50 values for the ACE inhibition are rather high (between 200 and 1500 micrograms/ml) in comparison to the IC50 of the NEP inhibition (between 40 and 2000 micrograms/ml). These results indicate that the basidiomycetes investigated seem to have a higher potential for the inhibition of the activity of NEP than of ACE. In general, basidiomycetes are a new source for inhibitors of metalloendopeptidases. Resulting from the isolation and characterization of these compounds new leading structures are expectable.

Heart rate variability: technique and investigational applications in cardiovascular medicine.

OBJECTIVE: To describe heart rate variability (HRV) analysis, especially time- and frequency-domain analyses, and some of its investigational applications in clinical cardiovascular medicine. DESIGN: We provide a brief introduction to the magnitude of sudden cardiac death and the factors that influence life-threatening ventricular arrhythmias as a backdrop to the potential importance of the autonomic nervous system and how this system might be assessed by the analysis of HRV. MATERIAL AND METHODS: We reviewed the literature from 1973 to 1994 that described beat-to-beat changes in heart rate, heart rate signal recording and processing, and investigational applications of HRV analysis to cardiovascular medicine. RESULTS: Beat-to-beat changes in heart rate are partly influenced by the autonomic nervous system. Briefly, changes in sympathetic input to the sinoatrial node affect low-frequency HRV, whereas changes in parasympathetic input affect high-frequency HRV. Multiple physiologic and nonphysiologic determinants of HRV exist, and therefore analysis of HRV as a direct "window" to autonomic tone is problematic. CONCLUSION: In selected patient populations, analysis of HRV yields important information about sinoatrial responsiveness to autonomic input and mortality risk stratification. Routine application of HRV analysis to clinical cardiovascular medicine awaits further investigation, however.

A finite-element facial model for simulating plastic surgery.

CAPS (Computer-Aided Plastic Surgery) is a prototype computer program that uses a three-dimensional graphic model of a human face and incorporates a finite-element mathematical model of the physical properties of the soft tissue. This program can estimate the biomechanic consequences of ablation and rearrangement of tissue. The results of two hypothetical surgeries on the face are presented: A surgeon could use this program as a sketch pad to predict and compare the outcome of facial plastic procedures on a patient-specific model. The relation of this program to previous work is discussed, and directions for research and possible applications are addressed.

A prospective study of the efficacy of various gloving techniques in the application of Erich arch bars.

PURPOSE: This is a prospective study of the efficacy of three different techniques of triple gloving during the application of Erich arch bars. Two different cut-resistant glove liners and three layers of latex gloves were compared with double gloving. METHODS AND MATERIALS: Thirty patients underwent Erich arch bar placement from first molar bilaterally on both arches. Two surgeons per case were arbitrarily placed into one of four groups that included double latex gloving, triple gloving with kevlar or stainless steel glove liners, or triple layer latex gloving, based on the availability of glove liners. All gloves were collected postoperatively and tested for perforation using water insufflation. RESULTS: One hundred eight of 120 outer gloves were perforated. There were 16 perforations in 11 inner gloves of the double latex glove group, but no perforations in the inner gloves of the triple latex glove group. There were two inner gloves with one perforation each in the stainless steel group and one glove with a perforation in the kevlar group. All techniques of triple gloving were found to be superior to double gloving. There was no difference between the techniques of triple gloving. CONCLUSION: During certain high-risk procedures greater protection to the surgeon can be obtained by triple gloving. The use of cut-resistant glove liners or triple layer latex gloving is superior to double layer latex gloving.

Narrow QRS complex tachycardias.

Regular narrow QRS complex tachycardias are a common problem encountered by general internists or family practitioners. Although such tachycardias often occur in patients with a normal heart and seldom represent life-threatening conditions, they may cause bothersome symptoms. The key to approaching the diagnosis of these arrhythmias is identifying atrial activity (P waves) on the surface electrocardiogram and classifying the tachycardia as long RP or short RP. On the basis of that information, a differential diagnosis can be generated, logical therapy can be delivered for termination of the tachycardia, and a plan can be developed to prevent recurrence. Because intravenously administered adenosine alleviates 90% of the episodes of supraventricular tachycardias and has minimal side effects, it has become the drug of choice for termination of most types of narrow QRS complex tachycardias.

A new method for assessment of cultured cardiac myocyte contractility detects immune factor-mediated inhibition of beta-adrenergic responses.

BACKGROUND: Potentially reversible congestive heart failure accompanies disease states associated with an immune cell myocardial infiltrate such as cardiac allograft rejection and inflammatory myocarditis. We therefore examined the hypothesis that immune cells can produce noncytotoxic alterations in cardiac function. METHODS AND RESULTS: A novel system to evaluate cultured cardiac myocyte contractility was developed using neonatal rat cardiocytes grown on human amniotic membrane segments. Spontaneous synchronous cell beating produced macroscopic distortion of these membranes. Movement of free-floating membranes anchored within a perfusion chamber was visualized under low-power microscopy and measured from recordings of the rhythmic displacement of membrane-adherent markers. Additions of graded concentrations of isoproterenol to the perfusate produced up to threefold increases in the initial contractile phase velocity (contractile index), with an EC50 of 10(-7) M. When the extracellular Ca2+ concentration was increased from 0.9 to 3.6 mM, 2.43-fold increases in this index occurred. Myocytes incubated for 72 hours in the presence of dilutions of medium conditioned by activated rat splenic macrophages and lymphocytes exhibited an isoproterenol contractile index inhibited by 62% compared with control cells. In contrast, responses of supernatant-exposed and control cells to increased extracellular Ca2+ concentrations were not significantly different. Parallel studies of increases in myocyte intracellular adenosine 3':5'-cyclic monophosphate concentrations in response to isoproterenol stimulation demonstrated correlative inhibition that was specific for exposure to medium conditioned by immune cells. CONCLUSION: Thus, a new method of in vitro cardiac contractility assessment that has significant advantages over existing systems has been developed and characterized. This new method has enabled description of an inhibitor of cardiac contractile function produced by activated immune cells.

Interleukin 1 and tumor necrosis factor inhibit cardiac myocyte beta-adrenergic responsiveness.

Reversible congestive heart failure can accompany cardiac allograft rejection and inflammatory myocarditis, conditions associated with an immune cell infiltrate of the myocardium. To determine whether immune cell secretory products alter cardiac muscle metabolism without cytotoxicity, we cultured cardiac myocytes in the presence of culture supernatants from activated immune cells. We observed that these culture supernatants inhibit beta-adrenergic agonist-mediated increases in cultured cardiac myocyte contractility and intracellular cAMP accumulation. The myocyte contractile response to increased extracellular Ca2+ concentration is unaltered by prior exposure to these culture supernatants, as is the increase in myocyte intracellular cAMP concentration in response to stimulation with forskolin, a direct adenyl cyclase activator. Inhibition occurs in the absence of alteration in beta-adrenergic receptor density or ligand binding affinity. Suppressive activity is attributable to the macrophage-derived cytokines interleukin 1 and tumor necrosis factor. Thus, these observations describe a role for defined cytokines in regulating the hormonal responsiveness and function of contractile cells. The effects of interleukin 1 and tumor necrosis factor on intracellular cAMP accumulation may be a model for immune modulation of other cellular functions dependent upon cyclic nucleotide metabolism. The uncoupling of agonist-occupied receptors from adenyl cyclase suggests that beta-receptor or guanine nucleotide binding protein function is altered by the direct or indirect action of cytokines on cardiac muscle cells.

In vivo effects of nifedipine and BAY 1 8201 on ceruletide induced gallbladder contraction.

Studies in animals suggest that calcium channel blockers may influence gallbladder contraction. In order to study possible actions in man we examined by ultrasonography the effects of two dihydropyridine derivatives, i.e. nifedipine (20 mg p. o.) and BAY 1 8201 (100 mg p.o.) on ceruletide induced human gallbladder contraction in 9 healthy male volunteers in a randomized, double-blind, three fold crossover study (latin square design). Blood samples for the measurement of plasma drug concentrations were drawn before and at regular intervals up to 8 h after drug ingestion. Ceruletide decreased gallbladder volumes by 52.1 +/- 8.2% (mean +/- 1 SEM) after nifedipine, 53.1 +/- 8.1% after BAY 1 8201 and by 59.3 +/- 10.1% after placebo (NS). Peak plasma concentrations of 53.7 x/: 2.3 ng/ml (geometric mean x/: geometric standard deviation) and of 35.5 x/: 1.5 ng/ml were reached after oral application of nifedipine and BAY 1 8201, respectively. We conclude that human gallbladder contraction in response to ceruletide is not markedly influenced by dihydropyridine derivates in the dosages used in this study. The results reported here stress the importance of calcium released from intracellular stores for the contractility of smooth muscle in the human gallbladder.